QTLs associated with growth traits and abdominal fat weight and their interactions with gender and hatch in commercial meat-type chickens

Associations between microsatellite markers and traits related to growth and fatness were investigated using resource broiler population. A sire-line x dam-line F₁ male was back-crossed to 12 dam-line females to produce 24 sires and 47 dams of the backcross 1 (BC₁) generation. These 71 parents were genotyped with 76 microsatellite markers. Following full-sib mating among the parents, 234 BC₁-F₂ progeny were phenotyped for five growth traits (body weight at 49 days from hatch, wog weight, front half weight, breast weight and tender weight) and abdominal fat weight. Maximum likelihood analysis was used to estimate the marker effects and to evaluate their statistical significance. Individual marker-trait analysis revealed 44 significant associations out of the 456 marker-trait combinations. Correction for multiple comparisons by controlling the false discovery rate (FDR) resulted in 12 significant associations at FDR = 10% with markers on chromosomes 1, 2, 5 and 13. Seventy-five percent of the 44 significant associations displayed no dependence on either hatch or gender; half of the remaining associations displayed dependence of the quantitative trait loci (QTL) effect on hatch x gender interaction. Thus, the analysed traits in this study may be dependent on external factors.